Electric switch



Oct.9, 1934. v,G APPLE 1,976,534

ELECTRIC SWITCH Filed Jan. 15, 1930 7-. INVENTOR.

5 3 Mnccnt G. flpp/c ATTORNEY points.

Patented Oct. 9, 1934 -UNITED STATES PATENT OFFICE ELECTRIC SWITCH VincerE GT Apple, Dayton, Ohio, assignor to Bendix Brake Company, South Bend, Ind., a

corporation of Illinois Application January 13,

8 Claims.

"circuit produces a high internal voltage or potential, thereby straining the insulation and causing arcing or burning at slightly opened switch An object of my invention is to eliminate this destructive arcing where switches are used in circuits of this type by so inserting resistance elements, as a portion of the switch itself, that the current strength or amperage is raised from a predetermined minimum to its full strength gradually but with sufilcient swiitness to satisfy the requirements of the ordinary make and break switch. To express the primary object of my invention somewhat differently, I have designed a switch which, 'when used in a circuit having an ppreciable amount of inductance or capacity, causes a gradual change iii-opening or closing the circuit thereby reducing the potential across the inductance or capacity.

Still another object of my invention has been to design a switch which,'by utilizing resistance elements or 'varying strength in conjunction therewith, may be utilized as a combination rheor stat and circuit closing mechanism for many purp ses. Among the varied applications which are obvious is its utilization with electric brakes for automotive vehicles.

Further objects and meritorious features of my invention will become apparent from the following description taken in conjunction with the drawing whereinlike numerals refer to like parts throughout and wherein: A

Fig. l is a cross section through the axis of my switch unit,

Fig. 2 is a cross section between the resistor elements and through the central terminal,

Fig. 3 is a plan view of the resistor end, and

Fig. 4 is a circuit diagram of the electrical connections for the switch as used in a circuit comprising a battery, an electric motor, and my switch.

In illustrating my invention 1 have disclosed one preferred embodiment wherein, the housin 10 is provided with two insulating tubes 12 in which are the resistance elements 14. These resistance elements I have indicated as carbon discs, although any other suitable resistance medium may be utilized, A metal plate member 1930, Serial No. 420,375

(on. eon-s1 16 connects the two resistance piles across their tops, while the plates 18 form a conductive hearing for the resistance elements 14. These plates 18 are insulated from the plate 20, which forms the bottom of my casing member, by means of the washers 22. This bottom plate '20 is secured in place by means of screws 24. The bolts 26, which are held in place by the nuts 28, and insulated by the washers 30, provide an external connection to the plates 18.

Concaved plates 32 of spring metal material bear against the plate 16 and function as springs for the purpose of normally retaining the operative elements of my switch inthe position shown in Fig. 1. These spring elements 32 likewise func-- 70 tion to assist in graduating the pressure exerted on the carbonpile discs through the medium of the balls 34. 7

Discs 36 serve to insulate the plates 32 from the plates 38, upon which latter plates the balls 34 have a direct bearing.

The cam rod 39, which is free to slide axially in my casing member, as clearly illustrated in F gs. land 2, is provided with peripheral grooves which are so located that when the said cam .0 rodis in its inoperative position (Fig. 1) movement in the direction of the arrow in Fig. 1 will first function to raise the ball 34 in the upper right hand comer of the quadrilateral formed by these four balls, then depress the lower left hand ball, then the lower right hand ball, and finally force the upper left hand ball man upward direction. It is likewise to benoted that the peripheral surface of this camming rod 39, at the end of each of the grooves, forms a concave por- .tion which serves to impart the pressure from the rods to the balls with gradually increasing force.

The upper balls 34 bear on the studs 40, the upper portion each of which is provided with a stem around whichv is placed a coil spring 42. The contact bridge members 44 are seated at the base of the stem upon the stud 40, forming bear-. ings for the coil springs 42, and in this way the said contact bridge members 44 are normally retained in their open position, bearing against the balls 34.

The terminals 46 are threaded into the insulating cover 48 of my casing and secured in place by means of the nuts 50. A bracket member 52, secured to the casing by means of the screws 54, serves as, a support for the switch unit when it is desired to secure it to an automotive vehicle or the like.

Although the operation ot my switch unit is obvious from the above description and the drawno value. on still further movement or the cam rod therein will be given.

When the cam rod 39 is pulled in the direction p i $970,534 ing, a brief sketch of the various stages involved or the arrow (Fig. 1) the ball 34 iii the upper right corner is forced upward; thus closing the circuit through the terminals brought in contact with the corresponding-switch blade 44, 0m 1m:- ther axialmovement oi-the cam rod-bathe lower left hand ball 34 will bear down on the plate 318 and transmit the pressure through the'platesbz',

36, and 16 to the left hand pile of carbon dimg:

thereby decreasing the resistance in this particular pile. Further movementoi the cam rod causes pressure to be applied to the ball 34, decreasing the res ce hand pile of carbon discs in the same manner. At this particular point the current or; amperage maybe regarded win its third stage and the resistance in the circuit at its rated in the circuit on initial -movement ot the cam rod and subsequently shuntod-cut-ot-circuit atthe final stage'oflits movement; '1- W s variou'smodtncationszot m deviceiwiil be. ap-

parent to those skilied -iin the art and for that reasonrmteno. torlimit-rnyselt only within the scopeortheapnendediclaims'rn Iz'clajm y :g;f: ."'i1" i," y. 1. An electric circuit control member comprising a housingpa pair orcarbonidiscpilesadiacent one-another: within the housing; terminals 100D necting the base of each =01: said carbompileswith the: exterior' ot thehousing, a plii'ralltyot contact 7 plates supported-in" the upper: portion on the housing and provided: on the: exteribcthereo! with terminal 'tacilities, cammingi means'azzlaliy slidable through said housing, andi'r'neans' whereby axial movement-or said caniming' means vvaries thesresistance. in saidicarbon .ipiles successively.

2. An ele'ctric'circult. control member comprise ing. a housing, carbon 'dMJPflBSlOGB-M adiacen't one another within-saidi housing, tim nections between; each of: saidepiiesthe sm-1 tericr of said. houslngeiavphmallty of contact plates. located witlun saidrhousingrand with terminal: iacilities on; the outside-there, contact bridge members adapted'to be actuated to bridge 1 said contact. platesand normally ire-1 tai'nedin open :circuit position withs respect tlmreto, and means operable to;- bridge two-oi; said contacts: and than for: successivelyiapplying; vanting pressures upoir each of said: piles 01- carbon discs.

3. In combination with asplurality of carbon piles, a pair: oi no'rmally open switch. elemmts; and a single-means associated'with eachor successively closing one switch, varying thei-tesiets .ancethrough the carbon: vein-fend closing the otheii switch:

4. An electric switch comprising a casing, a trio of contacts supported thereby, switch blades operable to bridge said contacts consecutivelma' pair of carbon piles housed within said'casihg and slidable camming means associated with said switch blades and carbon piles operable to first d empn irw 77 if and subsequently close the second pair of contacts. 7 5. In an electric circuit aswitch including a plurality of contacts, a plurality of resistance elei me,lit the resistance of which varies under pressure, a control device, means responsive to the V initiabmovemnt rsaid device to bridge twopf n helilhte saidcontacia anrlmake the circuit through said pun-amass elements, means responsive to iurther, continued movement of said device to successively compress said resistance elements "reducingthe resistance-thereoi successively and means responsive to still further continued move meet-er to bridge ewe contacts shunting the-fiance elemenla out oimt n. 1- l f 0.: m en-electric circuit e switcn omprisin a plurality of contacts, a plnralltyofi r the w: or whiclrvaries under pr, a nipulahle control member, responsive to the initial movement or said member to make saidresietors without pressure-thereon, means responsive to further continued movement of said control member {to vary thepressure-rm;-said re- Kwone either}: we. mum and whiie at m -.e

. u continued-movement or;-

- 7'. In-anelectrlc circuit a 'stvitch'cemprising a plurality sp ursnt otradiators, m; a movable control with sa e-mevabie-eenmlssmrcrer eaem mtor andm 'ntm u H am 51m" r t s wimmn ba i mmrew mor control mo ohm U shaft, said control shaft adapted under movement-opthaeoutrol shark to first bridge==two c tnrouga'said smothers-to meceseivei reduce-hie in -sai'rt' n" tc a-mini-125 i mmh briflge two othercoiitaets nmntmg: lfl l ealstorsout 75L- if. 8. In an electric circuit', a's'eifl-cmtamodiswitch v including as-pluralityrot eshtorsgasconmol-mem- 13 bar, operable upon movement -ot the I J "u "j responsive to continued; movamenbie s'aidicontrol I membor to through each or said resistors SUWWiIfldllC- ingswidtclrme'clmnlm .mi'm'thencosi-e tinned-memento! said? hmmberftheteatte'r teishunt said resistors outbttlremiaiouik T 

